The age of motoring innocence – albeit an increasingly dangerous age – came to an end with the introduction by then transport minister Barbara Castle of the breathalyser in October 1967. Ad hoc tests of sobriety such as making drivers stand on one leg, or walk a straight line, were thrust aside for a more scientific measure, though the breathalyser was initially only used for indicative purposes, a subsequent blood or urine test the actual evidential proof. Three years previously tests had hit on the blood alcohol level of 80mg of alcohol per 100ml as the limit beyond which driving was unsafe. The necessary legislation received royal assent in May 1967; and police forces were issued with the breathalyser equipment in preparation. The first driver to be tested happened to be stopped in Shropshire .
Somewhat incredibly there was major resistance to the very idea of the breathalyser test, and the 12-month driving ban for those caught over the limit. Even after the introduction Barbara Castle faced protests – at one public event a group of publicans berated her for the damage it was doing to their business. But in the first 12 months in which the device was used, and with the additional push of an advertising campaign, road deaths reduced by more than 1100, and serious injuries sustained in car accidents by more than 11,000. After such an impact few could argue that the action had not been both successful and necessary.